add_usage

langchain_core.messages.ai.add_usage(left: UsageMetadata | None, right: UsageMetadata | None) → UsageMetadata

Recursively add two UsageMetadata objects.

Example

from langchain_core.messages.ai import add_usage

left = UsageMetadata(
    input_tokens=5,
    output_tokens=0,
    total_tokens=5,
    input_token_details=InputTokenDetails(cache_read=3)
)
right = UsageMetadata(
    input_tokens=0,
    output_tokens=10,
    total_tokens=10,
    output_token_details=OutputTokenDetails(reasoning=4)
)

add_usage(left, right)

results in

UsageMetadata(
    input_tokens=5,
    output_tokens=10,
    total_tokens=15,
    input_token_details=InputTokenDetails(cache_read=3),
    output_token_details=OutputTokenDetails(reasoning=4)
)

Parameters:

• left (UsageMetadata | None)

• right (UsageMetadata | None)

Return type:

UsageMetadata